Thermoplastic resin-graft polyblend compositions

ABSTRACT

Thermoplastic resin compositions prepared by blending graftpolymers formed of rubbery copolymers obtained by copolymerizing a vinyl monomer with at least one compound selected from the group consisting of acrylic and methacrylic esters of tetrahydrofulfuryl alcohol, ethylene glycol monomethyl ether and 3-methoxybutanol, and at least one compound selected from the group consisting of aromatic vinyl compounds, vinyl cyanides, and mixtures of either of said types of compounds and monomers copolymerizable therewith, with polymers separately prepared from at least one compound consisting of either or combination of said aromatic vinyl compounds and vinyl cyanides.

United States Patent Yoshida et a1.

Apr. 1, 1975 [75] Inventors: Shuji Yoshida, Chiba; Tateo Iguchi,

lchihara. both of Japan [73] Assignee: Denki Kagaku Kogyo KabushikiKaisha, Tokyo, Japan [22] Filed: Mar. 12, 1974 [21] Appl No.1 450,298

Related U.S. Application Data [62] Division of Scr. No. 334.702.

[30] Foreign Application Priority Data Feb. 26. 1972 Japan 47-20045 U.S.Cl 260/876 R, 260/881, 260/885 Int. Cl. C081 41/12, C08f 29/56 Field ofSearch 260/876, 881

156] References Cited UNITED STATES PATENTS 3.275.712 9/1966 Siebcl ctal. 260/876 3.691.261) 9/1972 Mittnacht et al. 260/876 R 3.691.2619/1972 Cusano et a1. 260/881 Primary E.raminerMurray Tillman AssistantE.\'aminerC. J. Seccuro Attorney, Agent, or FirmKemon, Palmer &Estabrook [57] ABSTRACT Thermoplastic resin compositions prepared byblending graftpolymers formed of rubbery copolymers obtained bycopolymerizing a vinyl monomer with at least one compound selected fromthe group consisting of acrylic and methacrylic esters oftetrahydrofulfuryl alcohol, ethylene glycol monomethyl ether and3-methoxybutanol, and at least one compound selected from the groupconsisting of aromatic vinyl compounds, vinyl cyanides, and mixtures ofeither of said types of compounds and monomers copolymerizabletherewith, with polymers separately prepared from at least one compoundconsisting of either or combination of said aromatic vinyl compounds andvinyl cyanides.

6 Claims, No Drawings THERMOPLASTIC RESIN-GRAFT POLYBLEND COM POSITIONSThis is a division of application Ser. No. 334,702, filed Feb. 22,1973now U. S. Pat. No. 3,830,873.

This invention relates to thermoplastic resin compositions havingprominent weatherability, high impact strength and good moldability.

ln recent years. great demand has been made for thermoplastic resincompositions displaying prominent weatherability. high impact strengthand satisfactory moldability even when they are used as electric ormechanical parts in a state exposed to severe environmental conditions.To date, however. there has not been developed any resin product whichcan fully meet the above-mentioned requirements.

There will now be described the studies which have hither to been madeon thermoplastic resin compositions capable of presenting excellentweatherability,

high impact strength and good moldability. For example.acrylonitrile-styrene copolymers (hereinafter referred to as "AS") andpolystyrene (hereinafter referred to as PS") which present a low impactstrength,

though these resins themselves have excellent proper-' ties. have beendenatured for high impact strength into rubbery substances of conjugateddiene series such as butadiene polymer or styrene-butadiene rubber(hereinafter referred to as -'SBR") and accepted in wide fields underthe name of ABS or Hl-PS (high impact polystyrene). However. said ABSand Hl-PS have an extremely low weatherability. This originates with thefact that butadiene series rubber itself has little weatherability andis readily subject to deterioration upon exposure to light. To eliminatesuch drawbacks, attempts have been made to incorporate a stabilizer.ultraviolet ray absorbent or a certain kind ofpigment in the aforesaidABS and Hl-PS. Even these attemps have failed to enable the resinsconstituting said compositions to retain their original properties dueto deterioration when the compositions are used long out of doors. Toobtain prominent weatherability essentially, therefore, it has beenproposed to replace the above-mentioned rubbers of conjugated dieneseries by other rubbers free from unsaturated bonds and displaying goodweatherability by themselves. such as ethylene-propylene rubber(hereinafter referred to as EPR"), ethylene-vinyl acetate copolymerrubber (hereinafter referred to as E\-'A") or rubber of acrylic esterseries (hereinafter referred to as -'ACR'").

However. EPR, EVA and ACR are little compatible with hard and brittleresins such as A5, PS and polymethyl methacrylate which are desired tohave high impact strength. Therefore. EPR, EVA and ACR have to begraftpolymerized in advance with a suitable monomeric component which isessentially compatible with said hard brittle resins. In fact. however,EPR, EVA or ACR constituting a base polymer is already saturated, sothat the molecules of said base polymer have very few active points forgrafting with said monomeric component, obstructing sufficient grafting.Therefore, a graftpolymer of may be EPR, EVA and ACR with said monomericcomponent presents great difficulties in imparting high impact strengthto the aforesaid brittle resins such as AS and PS due to theinsufficient compatibility of any of EPR. EVA and ACR with the aforesaidmonomeric component.

Attemps have been made to improve the activity of saturated rubbers suchas EPR, EVA and ACR with respect to graftpolymerization. some of theattempts consist in, for example, growing peroxides in the molecules ofa base polymer by oxidation before graftpolymerization is commenced,introducing a new polymerizable double bond group into the molecules ofthe base polymer or treating said base polymer with radiation. All theseprocesses represent pretreatments preceding graftpolymerization and areintended to increase active points for graftpolymerization of the basepolymer, largely affecting the physical properties of a finalgraftpolymerized product. Therefore, said process are subjectto variouslimitations with respect to the environments and conditions in whichsaid processes are carried out, and technically very much complicated.Moreover, these additional pretreatments eventually result in highproduction cost.

On the other hand, the Japanese Patent Publications Nos. 33193/ 1376/72and 11826/72 set forth a method of first preparing a base polymer bycopolymerizing acrylic esters of C alcohols with cycloalkenyl esters andthen producing a graftpolymer by radical polymerization of said basepolymer with, for example, an aromatic vinyl monomer. However, none ofthe above-mentioned methods distinctly disclosed whether the productcould display prominent weather ability and high impact strength. Inaddition, the Japanese Patent Publications Nos. 8987/70 and 17472/62 andU.S. Pat. No. 3,275,712 indicated description on the production of resincompositions having excellent weatherability and impact strength usingmethods similar to those shown in the first group of patents. The lattergroup of patents gave suggestions neither on the resolution of thepreviously mentioned drawbacks nor on any of the conventional processesof manufacturing resin compositions displaying such desired properties.

One of the prior art processes consisted in graftpolymerizingacrylonitrile and styrene with, for example polybutyl acrylate in thestate of latex. The present inventors tested said process under variousconditions. However, a resin composition obtained did not present highimpact strength. This invention has been accomplished to eliminate theshortcomings of all the aforementioned proposed processes and isintended to provide thermoplastic resin compositions displayingexcellent weatherability, impact strength and moldability. Thisinvention comprises thermoplastic resin compositions prepared by thesteps of copolymerizing 0.5 to 25 parts by weight of at least onecompound selected from the groups consisting of acrylic and methacrylicesters of tetrahydrofulfuryl alcohol, ethylene glycol monomethyl etherand 3-methoxybutanol with 99.5 to 75 parts by weight of monomersconsisting of alkyl acrylate wherein the alkyl group has 2 to 8 carbonatoms to obtain a rubbery copolymer A which is the same as the aforesaidbase polymer; graftpolymerizing parts by weight of said rubberycopolymer A with 100 to 300 parts by weight of at least one compoundselected from the group consisting of aromatic vinyl compounds, vinyleyanides and mixtures of either of said both types of compounds andmonomers copolymerizable therewith in the presence of 0 to 0.5 parts byweight of a chain transfer reagent to obtain a graftpolymer B; andblending said graftpolymer B with a polymer C separately prepared fromat least one compound consisting of either or combination of aromaticvinyl compounds and vinyl cyanides so as to cause said graftpolymer B tobe uniformly dispersed in particle sizes of 150 to 1000 millimicrons insaid polymer C. Thermoplastic resin compositions of this invention areprepared by effectingreactions in the following three steps. Step I:

0.5 to parts by weight by at least one compound selected from the groupconsisting of acrylic and methacrylic esters of tetrahydrofulfurylalcohol (abbreviated as THF), ethylene glycol monomethyl ether(abbreviated as MOE) and 3-methoxy butanol (abbreviated as MOB) arecopolymerized with 99.5 to 75 parts by weight of vinyl monomerconsisting of alkyl acrylate wherein the alkyl group has 2 to 8 carbonatoms to obtain a rubbery copolymer A;

Step II:

100 parts by weight of said rubbery copolymer A are graftpolymerizedwith 100 to 300 parts by weight of at least one compound selected fromthe group consisting of aromatic vinyl compounds, vinyl cyanides andmixtures of either of said both types of compounds and monomerscopolymerizable therewith in the presence o f0.5 part by weight or lessalkyl mercaptan as a chain transfer reagent to obtain a graftpolymer B;

Step lll:

Said graftpolymer B is uniformly dispersed in 150 to 1000 millimicronparticles in a hard brittle polymer C separately obtained from at leastone compound consisting of either or combination of aromatic vinylcompounds and vinyl cyanides.

Referring to Step I. the rubbery copolymer A readily admits ofgraftpolymerization without using any pretreatment required in the priorart and in consequence under the sameconditions as in the ordinarygrafting process applied in the manufacture of ABS resin. Said ordinarygrafting process is set forth in the US. Pat. No. 3,168,593.

Said ordinary grafting process indeed enables the rubbery copolymer Aobtained in Step I to be fully copolymerized with a compound which iscompatible with PS and AS which are desired to have high impactstrength, and causes the interfaces of the particles of the rubberycopolymer A to have a close affinity with polymer C. Accordingly theresultant composition indicates extremely good moldability to provide avery gloss product. In fact, however, application of said graftingprocess alone has been found insufficient to impart high impact strengthto molded articles. The present inventors further study on this pointshows that resin compositions can not be furnished with high compactstrength, unless the graftpolymer B obtained in Step ll is uniformlydispersed in the hard brittle polymer C in larger particles than 150millimicrons on the average. Where the graftpolymer B has a particlesize exceeding 1,000 millimicrons, then the molded product will decreasein gloss. Therefore the particle size of the graftpolymer B should fallwithin the range of 150 to 1000 millimicrons, or preferably 200 to 800millimicrons. In this case, said particle size need not always beuniform. Where, however, the particle size has an ununiformdistribution, it is necessary that the respective particles should onlydiffer in size by less than one micron.

The rubbery copolymer A used in the method ofthisinvention shouldinclude 0.5 to 25 parts by weight of an acrylic or methacrylic ester ofTHF, MOE or MOB'or a mixture thereof.

The ester of alkyl acrylate (where the alkyl group has 2 to 8 carbonatoms) constituting the other component of the rubbery copolymer A mayinclude other copolymerizable monomers such as styrene, acrylonitrile,vinyl ethers and esters of alkyl methacrylate such as methylmethacrylate and 2 -ethylhexyl methacrylate, insofar as the glasstransition temperature (abbreviated as Tg) of the rubbery copolymer Adoes not exceed l0C. Where said glass transition temperature increasesover l0C, then the resultant resin composition will noticeably decreasein impact strength at a lower temperature than 0C. Accordingly, the Tgshould be lower than -l0C or preferably C. Further, if required, it ispossible to add 1 percent or less of polyfunctional compounds capable ofcross linking such as divinyl benzene and dimethacrylate.

Dispersion of the graftpolymer B in the polymer C in particle sizes of150 to 1,000 millimicrons can be practically carried out by bringing theoriginal copolymer A to a latex form having the prescribed particlesizes of t 150 to 1,000 millimicrons by emulsion polymerization.

Formation ofa latex copolymer having such large particle size can beeffected by the customary process of making a condensed rubbery latex ofpolybutadiene series.

The graftpolymer B is prepared by graftpolymerizing parts by weight (insolid form) of the latex copolymer A with 100 to 300 parts by weight ofat least one compound selected from the group consisting of aromaticvinyl compounds, vinyl cyanides and mixtures of either of said bothtypes of compounds and monomers copolymerizable therewith by means ofradical polymerization in the presence of() to 0.5 part by weight of achain transfer reagent. In this case. addition of less than 100 parts byweight of said mixtures of either of the aforesaid both types ofcompounds and monomers copolymerizable therewith is not sufficient toimpart desired properties to a final resin composition. An optimumaddition of said mixture ranges between and 200 parts by weight.Further, addition of a chain transfer reagent consisting of alkylmercaptans such as tertpauryl mercaptan is chosen to be to 0 to 0.5 partby weight, but preferred to fall within the range of0 to 0.3 part byweight. It is practically advantageous to carry out graftpolymerizationby emulsion polymerization.

A compound grafted to the rubbery copolymer A is preferred to be atleast one compound selected from the group consisting of 20 to 100percent by weight of aromatic vinyl compounds, 40 to 0 percent by weightof vinyl cyanides or 0 to 70 percent by weight of mixtures of either ofsaid both types of compounds and monomers, for example, methylmethacrylate copolymerizable therewith.

A group of aromatic vinyl compounds used in graftpolymerization includesstyrene, a-methyl styrene and chlorostyrene, and another group of vinylcyanides used in said copolymerization includes acrylonitrile andmethacrylonitrile. The graftpolymer B obtained in Step ll which iscompatible with the hard brittle polymer C should preferably be blendedwith said polymer C in sufficient proportions to effect fullcompatibility therewith. Said polymer C may consist of the same type ofaromatic vinyl compounds or vinyl cyanides as those used in preparingsaid graftpolymer B.

The graftpolymer B may be directly blended with the polymer C whichconsists of, for example, PS emulsion, AS emulsion or an emulsion ofa-methyl styrene- 5 styreneacrylonitrile copolymer. The. blended massmay later be solidified with addition of inorganic salting out reagents.Or it is possible first to coagulate the graft copolymer 8 with additionof a proper reagent and then 6. AS resin was blended on the roll at 170Cwith the powdered graftpolymer so that the rubbery-component derivedfrom said powdered graftpolymer amounted to 25 percent of the wholecomposition. When tested for the blend said copolymer B thus coagulatedwith the sepa- 5 physical properties, the composition indicated a veryrately prepared polymer C on a roll or by an extrudcr. large lzod impactvalue of 35'kg.cm /cm (as measured Where required, additives such asastabilizer and pigaccording to the AmericanStandards for TestingMatement may be incorporated in the mass in. carrying out rials(abbreviated as ASTM)-D256). said blending. Control 7 A thermoplasticresin composition prepared by the Thls e.xperm.lem represents a controlcamied out q I I comparison with Example 1. An autoclave with an ag1-abmementroned method of this invention displays very tit h th c min dair re laced b nitro en 15 prominent weatherability, impact strength andmoldf fi i i b t lit ability and is adapted for application in widefields and, i C 0 u y glf't particularly due to excellentweatherability. most suit- H able as electrical or mechanical parts usedin a state exg 38 in f g i a g posed to various environmentalconditions. i f f? i g l a i This invention will be more fullyunderstood by refer- $128 0 f 2 i g i th en 5: i i gg ence to theexamples and controls which follow. p0 ymer was ur er m e sa e Example1, the product mdtcated an lzod impact value EXAMPLE 1 30 of 2.5kg.cm/cm, proving that the product had its properties noticeablyaffected by such a small size as 80 mil- 1 In an autoclave with anagitator were charged 450g licrons of butyl acrylate. 50g of THF. 2.5gof an emulsifier ftnanufactured by Kao Soap Company under a treade-EXAMPLE 2 mark Emal No. 0). 0. lg of potassium persulfate as aPolymerization was carried out in the same manner polymerizationcatalyst and 200g of water. The air in as in Example 1, excepting thatthe rubbery latex cothe autoclave was fully replaced by nitrogen gas andpolymer obtained in Step I of Example 1 consisted of polymerization wascarried out at 50C. When the concomponents having the proportions givenin Table 1 version reached to 40 percent, 300g of water was furbelow, inwhich the unit is part by weight. Treatments ther added. Later thepolymerization attained a degree of Steps II and Ill were conductedinthe same manner of 98 percent in 6 hours and the average latex particleas in Example 1. A resin composition obtained showed size was 350millimicrons. When observed by an electhe properties whose measuredvalues are give "in" tronic microscope, said latex consisted ofparticles Table 2. v i

Table 1 Sample MOE MOB THF Butyl Z-ethyl- Styrene Acrylo- Z-cthylene No.acrylate hcxyl nitrile hcxyl acrylatc methacrylate l l 99 q 2 5 95 3 5so t5 4 5 95 I 5 20 so 6 l0 50 7 5 5 75 10 5 8 t 69 20 l0 9 t5 40 t0 t025 10* 100 50 12* so to t0 *controls whose sizes widely extended over arange of 150 to 900 Table 2 millimicrons.

Tensile Elongation 2. 200g ofsaid latex co olvmer, l of Emal No. 0 andSamplc lmpilct smnglh MclLindcX O 1 f d d I No. strength at yield pointbreak point g/l0 min. g o po assium pcrsu ate were Intro uce onto anmom/Cm kglmmg (3) q (2) (3) autoclave with an agitator having the atrtherein prevt- (l) ously replaced b\ nitrogen gas. Further. 600g ofwater i I v 1 4o 3.8 40 13 was added. A mixture ol l40g of styrene. gof-acrylo- 3 35 440 i5 nitrile and 0.2g of tert-lauryl mercaptan-wasadded 0 3 g continuously in two hours at (10C so as to obtain 30 2 g5;:1 percent concentration of solids upon completion of 6 36 4.1 37 t4t... 7 35 4.1 35 I5 graltpolymerizatton. .Thc latex astoagulatcd by the8 H 41 3; H addition ol 2.000g of 10 PCI'QCHLCLIC/gjlfl]. and the mix- 935 41 1' 35 I 1 ture was heated to (..lt was filtered and washedrcs ll20 3 I 1 ll? 4.3 3.1 20 3 peatedly \Hlll ater and dried at (10 C. 3.3 I30 3 3. There was separately prepared by suspension poly- T -DZSfitnerilation AS resin containing 30 percent acrylonitrile and having atotal molecular weight of 100,000. The

31 AS'lhfDoSh 3 l AS'l'M-DIIRK. excepting that the load as 5 kg and thetemperature was 2501' controls Moldings obtained from Samples 1 to 9presented a good appearance and gloss. whereas moldings derived fromSamples to 12 were less lustrous and, when annealed, contractedthemselves as much to lose their original forms, and, further as seenfrom Table 2, prominently decreased in impact strength and othermechanical properties.

WE-2") at-50C and without pouring water over the tester, the resultsbeing presented in Table 4.

As apparent from Table 4, the resin compositions of this inventionindicated far more excellent weatherability than said ABS commerciallyknown as Dcnka ABS-GR 3.000."

Table 4 Impact strength kgcm/em Note: The commercially available ABS wasmanufactured by Denki Kagaku Kogyo Kahushiki Kaisha under a trademarkDenka ABS (IR-3000.

EXAMPLE 3 Resin compositions listed in Table 3 below were prepared inthe same manner as in Example 1. excepting that the initial rubberycopolymer had the same composition as Sample 4 of Example 2 and theamounts of compounds being grafted and that of tart-lauryl mercaptanwere changed. The impact strength of the resin compositions obtained wasmeasured, the results being given in Table 3 in which the unit part byweight.

EXAMPLE 5 There were prepared by the customary process a latex ofpolybutylacrylate concentrated at 30 percent 30 and having an averageparticle size of 100 millimierons and a latex copolymer formed of butylacrylate-S percent THF and concentrated to the same extent as the firstmentioned latex and consisting of particles whosle size similarlyindicated 100 millimicrons on the aver- Table 3 Grafted compounds impactSample Ruhhery Styrene Acrylo- Methacrytert-laur-yl strength No.copolymer Nitrile late mercaptan kg.cm/cm l-l do. do. do. 0 0.2 29

do. I40 60 0 0 35 I6 do. do. do. 0 0.4 30

I7 do. 210 90 0 0 36 I8 do. do. do. 0 0.3 34

I) do. do. do. 0 (L5 30 do. 60 (l 90 0.1

ll do. 40 30 70 0. l 3] 22" do. I5 0 0 o 24* do. I 0 0.6 5

25* do. 2H) 90 0 0.6 5

c ntrols The above Table 3 clearly shows that Samples 13 to 21 accordingto this invention displayed for higher impact strength than Samples 22to 25 falling outside of the invention.

' EXAMPLE 4 Samples 2. 4, 5. 7 and 9 of Example 2 were tested forweatherability by irradiating carbon arcs thereon using an instrument ofweathering test (manufactured by Toyo Rika Kogyo Kabushiki Kaisha undera trademark 300g of each latex was mixed with 200g of water, lg ofsodium dodecylbenzene sulfonate and 0.3g of potassium persulfate. Whilethe mixture was stirred in atmosphere of nitrogen gas, g of styrenemonomer was added in small proportions to complete copolymerization. Themixture of graftpolymer and styrene homopolymer obtained was separatedinto the respective components by fractionation usingmethylethyl-ketonmethyl alcohol. The results are shown in Table 5.

Table Type of latex (iral't- Homopoly mcr Graft efficiency polymer ('2of polystyrene (opolymer of )5 9; BUTYL ACRYLATE 8] I) 2 AND 5% THF 5 '2THF *lolybutylacrylate 3 47 Note: c ntrol Table 5 shows that whilegrafted styrene was only 6% in the case of polybutylacrylatc, it was 62percent in the case ofthc rubbery copolymer of this invention thoughsaid copolymer contained only 5% THF, providing that even if only 5percent THF is used as one ofthe ingredients ofthe rubbery copolymer.graft efficiency is prominently elevated on account of numerous activepoints on THF. The graft efficiency was determined as follows:

Each latex was used in an amount of 300g, at "/1 concentration and in astate containing 90g of solids. 90g of styrene was used as a graftmonomer. Therefore, the rubbery copolymer and the styrene monomerrespectively amounted to percent of the mass used in said determination.

Graft Efficiency (8l-5()/50) X l()() 62 percent (this invention) GraftEfficiency (535()/50) X 100 6 percent (control) What we claim is:

l. Thermoplastic resin compositions prepared by the steps ofcopolymerizing 0.5 to 25 parts by weight of at least one compoundselected from the group consisting of acrylic and methacrylic esters ofethylene glycol monomethyl ether with 99.5 to parts by weight ofmonomers consisting of alkyl acrylate wherein the alkyl group has 2 to 8carbon atoms to obtain a rubbery copolymer A; graftpolymerizing parts byweight of said rubbery copolymer A with I00 to 300 parts by weight of atleast one compound selected from the LII LII

group consisting of aromatic vinyl compounds, vinyl cyanides andmixtures of either of said both types of compounds and monomerscopolymerizable therewith in the presence of 0 to 0.5 parts by weight ofa chain transfer reagent to obtain a graftpolymer B; and blending saidgraftpolymer B with a polymer C separately prepared from at least onecompound consisting of aromatic vinyl compounds, vinyl cyanides andmixtures thereof so as to cause said graftpolymer B to be uniformlydispersed in particle sizes of to 1000 millimicrons in said polymer C.

2. Resin compositions according to claim 1 wherein the vinyl monomerspartly constituting the rubbery copolymer A are prepared byincorporating in the alkyl acrylate at least one compound selected fromthe group consisting of styrene, acrylonitrile, vinyl ethers andmethacrylic esters, insofar as the glass transition temperature of saidrubbery copolymer A does not exceed l()C.

3. Resin compositions according to claim 1 wherein the aromatic vinylcompound is at least one compound selected from the group consisting ofstyrene, a-methyl styrene and chlorostyrene. and vinyl cyanide is atleast one compound selected from the group consisting of acrylonitrileand methacrylonitrile.

4. Resin compositions according to claim 1 wherein one of the monomerscopolymerizable with either of the aromatic vinyl compounds and vinylcyanides is a methacrylic ester.

5. Resin compositions according to claim 4 wherein the methacrylic esteris methyl methacrylate.

6. Resin compositions according to claim 1 wherein said compoundgraftpolymerized with the rubbery copolymer A is 20 to 100 percent byweight of aromatic vinyl compounds, 40 to 0 percent by weight of vinylcyanides and 0 to 70 percent by weight of mixtures of either of saidboth types of compounds and monomers copolymerizable therewith.

1. THERMOPLASTIC RESIN COMPOSITIONS PREPARED BY THE STEPS OFCOPOLYMERIZING 0.5 TO 25 PARTS BY WEIGHT OF AT LEAST ONE COMPOUNDSELECTED FROM THE GROUP COISISTING OF ACRYLIC AND METHACRYLIC ESTERS OFETHYLENE GLYCOL MONOMETHYL ETHER WITH 99.5 TO 75 PARTS BY WEIGHT OFMONOMERS CONSISTING OF ALKYL ACRYLATE WHEREIN THE ALKYL GROUP HAS 2 TO 8CARBON ATOMS TO OBTAIN A RUBBERY COPOLYMER A, GRAPHPOLYMERIZING 100PARTS BY WEIGHT OF SAID RUBBERY COPOLYMER A WITH 100 TO 300 PARTS BYWEIGHT OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OFAROMATIC VINYL COMPOUNDS, VINYL CYANDIES AND MIXTURES OF EITHER OF SAIDBOTH TYPES OF COMPOUNDS AND MONOMERS COPOLYMERIZABLE THEREWITH IN THEPRESENCE OF 0 TO 0.5 PARTS BY WEIGHT OF A CHAIN TRANSFER REAGENT TOOBTAIN A GRAFTPOLYMER B, AND BLENDING SAID GRAFTPOLYMER B WITH A POLYMERC SEPARATELY PREPARED FROM AT LEAST ONE COMPOUND CONSISTING OF AROMATICVINYL COMPOUNDS, VINYL CYANDIES AND MIXTURES THEREOF SO AS TO CAUSE SAIDGRAFTPOLYMER B TO BE UNIFORMLY DISPERSED IN PARTICLE SIZES OF 150 TO1000 MILLIMICRONS IS SAID POLYMER C.
 2. Resin compositions according toclaim 1 wherein the vinyl monomers partly constituting the rubberycopolymer A are prepared by incorporating in the alkyl acrylate at leastone compound selected from the group consisting of styrene,acrylonitrile, vinyl ethers and methacrylic esters, insofar as the glasstransition temperature of said rubbery copolymer A does not exceed-10*C.
 3. Resin compositions according to claim 1 wherein the aromaticvinyl compound is at least one compound selected from the groupconsisting of styrene, Alpha -methyl styrene and chlorostyrene, andvinyl cyanide is at least one compound selected from the groupconsisting of acrylonitrile and methacrylonitrile.
 4. Resin compositionsaccording to claim 1 wherein one of the monomers copolymerizable witheither of the aromatic vinyl compounds and vinyl cyanides is amethacrylic ester.
 5. Resin compositions according to claim 4 whereinthe methacrylic ester is methyl methacrylate.
 6. Resin compositionsaccording to claim 1 wherein said compound graftpolymerized with therubbery copolymer A is 20 to 100 percent by weight of aromatic vinylcompounds, 40 to 0 percent by weight of vinyl cyanides and 0 to 70percent by weight of mixtures of either of said both types of compoundsand monomers copolymerizable therewith.